1. Field of the Invention
[0001] This invention relates to fuel injection control apparatus and method for a direct
injection internal combustion engine in which fuel is injected from a fuel injection
valve directly into an engine combustion chamber.
2. Description of the Related Art
[0002] Normally with fuel injection control in a direct injection internal combustion engine,
operation of the fuel injection valves is controlled in response to a target injection
quantity that is calculated based on the operating state of the engine, such as engine
speed and engine load. The fuel injection quantity is then adjusted to an amount that
is suitable for the engine operating state at that time.
[0003] An apparatus for performing this kind of fuel injection control, which increase-corrects
the fuel injection quantity at start-up when the engine is cold is widely known (see
JP(A) 2004-225658, for example). This increase correction is performed to both improve the combustion
state and facilitate early warming-up of an exhaust gas control catalyst provided
in the engine exhaust passage.
[0004] Furthermore, a fuel injection control apparatus is also known which switches the
fuel injection mode between a batch injection in which the fuel is injected all at
once, and a split injection in which the fuel is injected in a plurality of separate
injections (see
JP(A) 2003-65121, for example). Switching the fuel injection mode in this way enables the fuel injection
state to be finely controlled in a manner appropriate for the engine operating state
and the engine temperature and the like.
[0005] In a fuel injection control apparatus that performs an increase correction, such
as that described above, however, the following problems occur when performing fuel
injection control while switching between a batch injection and a split injection.
[0006] That is, the amount of fuel that actually contributes to combustion may be less than
the amount of fuel injected from the fuel injection valve due to some of the injected
fuel adhering to the inside wall of the engine combustion chamber when the engine
is cold. As a result, the amount of fuel that actually contributes to combustion changes,
which affects the combustion state. Also, the amount of fuel that adheres to the inside
wall of the engine combustion chamber changes depending on the fuel injection timing.
This is because the area of the inside wall that is exposed in the combustion chamber
changes as the engine piston (hereinafter simply referred to as "piston") moves, and
the position of the piston changes depending on the fuel injection timing. Moreover,
in addition to the fuel injection timing, the period of time between when fuel is
injected and when it is ignited, i.e., the time required for the fuel to vaporize,
differs which also affects the amount of fuel that adheres.
[0007] Also, the direction of movement and the speed of the piston, or the actual volume
of the combustion chamber, differs depending on the fuel injection timing, which affects
the extent to which injected fuel is vaporized. As the extent to which injected fuel
is vaporized changes, the amount of fuel that actually contributes to combustion also
changes, which in turn changes the combustion state.
[0008] Therefore, even if the amount of fuel is increased in the same way when a batch injection
is performed as it is when a split injection is performed, the amount of fuel contributing
to combustion is different. Thus there still remains room for improvement in this
area.
SUMMARY OF THE INVENTION
[0009] In view of the foregoing circumstances, this invention aims to provide a fuel injection
control apparatus for a direction injection internal combustion engine including on
ignition device, which can, in an internal combustion engine in which the fuel injection
mode switches between batch injection and split injection, appropriately increase
the amount of fuel injected according to the extent to which fuel vaporizes and the
extent to which fuel adheres to the combustion chamber wall in each injection mode.
[0010] Hereinafter, the means for achieving the foregoing aim and the operational effects
thereof will be described.
A first aspect of the invention relates to a fuel injection control apparatus for
a direct injection internal combustion engine, which, when the engine is cold, switches
a fuel injection mode between a batch injection in which fuel is injected once at
the end of a compression stroke and a split injection in which fuel is injected at
a plurality of timings including at least at the end of the compression stroke, and
which is provided with increase correcting means for setting a fuel increase amount
larger for the split injection than for the batch injection when increase-correcting
a fuel injection quantity set based on an engine operating state.
[0011] When the engine is cold, fuel that is injected is not sufficiently vaporized. As
a result, some of that fuel tends to adhere to the inside wall of the combustion chamber.
Also, when the piston is on the top-dead-center (TDC) side, as it is at the end of
the compression stroke, the exposed area of wall inside the engine combustion chamber
(hereinafter simply referred to as "combustion chamber") is small so fuel adherence
is inhibited somewhat. Even so, when fuel is injected at a time other than at the
end of the compression stroke, such as at the beginning of the compression stroke,
the amount of fuel that adheres increases, reducing the percentage of injected fuel
that actually contributes to engine combustion.
[0012] In view of this, with the structure according to the first aspect of the invention,
when the fuel injection quantity that is set based on the operating state of the engine
is increase-corrected, the fuel increase amount is set to be larger for a split injection
than it is for a batch injection. Therefore, during a split injection, even if the
amount of fuel that adheres to the inside wall of the engine combustion chamber increases,
a substantive insufficiency in the fuel injection quantity due to that increase, and
thus deterioration of the combustion state due to that insufficiency, is able to be
inhibited.
[0013] According to a second aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to the first aspect of
the invention, the increase correcting means sets the fuel increase amount based on
at least one of an engine temperature and a time elapsed after engine start-up.
[0014] The amount of fuel that adheres to the inside wall of the engine combustion chamber
tends to increase the lower the engine temperature, and the temperature of the engine
combustion chamber is lower the less time that has elapsed after engine start-up.
Accordingly, the amount of fuel that adheres to the inside wall of the engine combustion
chamber (hereinafter also referred to as "fuel adhering amount") tends to increase
the shorter that elapsed time.
[0015] With respect to this, with the structure according to the second aspect of the invention,
when the fuel injection quantity is increase-corrected so that the fuel increase amount
is larger for a split injection than it is for a batch injection, that fuel increase
amount can be set in view of the fuel adhering amount which changes in response to
the engine temperature or the time that has elapsed after engine start-up. Accordingly,
it is possible to ensure the amount of fuel that actually contributes to combustion
and thus further stabilize the combustion state. The engine temperature can be estimated
based on, for example, the engine coolant temperature or the engine lubricating oil
temperature.
[0016] According to the third aspect of the invention, the fuel injection control apparatus
for a direct injection internal combustion engine according to first or second aspect
of the invention further includes split rate setting means for setting an injection
quantity split rate of each injection when the fuel injection mode is set to the split
injection. Further, the split rate setting means sets the injection quantity split
rate of each injection such that the difference between the injection quantity split
rates becomes less the smaller the total quantity of fuel injected by all of the injections
of the split injection.
[0017] Typically, when the target fuel injection quantity is small, i.e., when the total
quantity of fuel to be injected by all of the injections in a split injection is small,
the operational response of the fuel injection valve must be extremely fast because
the interval between the time that the fuel injection valve is open and the time that
it is closed is short. As a result, if the fuel injection quantity of any of the injections
is set too small, it is possible that the fuel injection may not be able to be performed
properly due to a limit in the operational response of the fuel injection valve.
[0018] Regarding this, with the structure according to the third aspect of the invention,
when the total quantity of fuel injected by the injections of the split injection
is small, i.e., when the fuel injection quantity of any of the injections is extremely
small depending on the setting of the injection quantity split rates, the injection
quantity split rates of the injections are set so that the difference between them
is small. Accordingly, it is possible to inhibit, to the greatest extent possible,
the fuel injection quantity of each injection in a split injection from becoming too
small, thus making it possible to ensure proper fuel injection operation in each injection.
The fuel injection quantity can be calculated based, for example, on the engine speed,
the intake air amount, or furthermore, the time elapsed after engine start or the
engine temperature that is estimated from the engine coolant temperature or the like.
[0019] According to a fourth aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to the third aspect of
the invention, the split rate setting means sets the injection quantity split rate
of each injection so that the injection quantity split rates become equal when the
total quantity of fuel injected by all of the injections of the split injection is
equal to, or less than, a predetermined quantity.
[0020] With this structure, when the total quantity of fuel to be injected by all of the
injections of a split injection is equal to, or less than, a predetermined value,
i.e., when the total fuel injection quantity is split unevenly and the fuel injection
quantity of an injection may fall below the minimum fuel injection quantity of the
fuel injection valve, the injection quantity split rates of the injections are set
to be equal. It is therefore possible to avoid, to the greatest extent possible, a
situation occurring in which normal injection is no longer possible due to a fuel
injection quantity of one of the injections of a split injection falling below the
minimum fuel injection quantity of the fuel injection valve. As a result, split injections
can be executed more often.
[0021] According to a fifth aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to the third or fourth
aspect of the invention, the split rate setting means sets the injection quantity
split rate of each injection such that the fuel injection quantity of the injection
at the end of the compression stroke is larger than the fuel injection quantity of
any other injection when the total quantity of fuel injected by all of the injections
of the split injection is greater than a predetermined value.
[0022] As described above, if the total quantity of fuel injected by all of the injections
of a split injection is small, the operational response of the fuel injection valve
becomes an issue. On the other hand, however, when the total quantity of fuel injected
is large, there is a high degree of freedom when setting the injection quantity split
rates of the injections in a split injection. Therefore, with the structure according
to the fifth aspect of the invention, when the total quantity of fuel to be injected
is large, the injection quantity split rates are set such that the fuel injection
quantity of the injection at the end of the compression stroke is larger than the
fuel injection quantity of any other injection. As a result, so-called stratified-charge
combustion can be performed stably.
[0023] According to a sixth aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to any one of the first
to the fifth aspects of the invention, the increase correction of the fuel injection
quantity is performed when the engine is idling until a predetermined period of time
has elapsed after engine start-up.
[0024] Here, an apparatus is known which increase-corrects the fuel injection quantity while
injecting fuel at the end of the compression stroke in order to raise the exhaust
gas temperature when the engine is idling until a predetermined period of time has
elapsed after engine start-up. With the structure according to the sixth aspect of
the invention, when the fuel injection mode is switched between batch injection and
split injection in such an apparatus, a fuel increase can be performed of an amount
that is appropriate in view of the extent to which fuel adheres to the inside wall
of the combustion chamber in each injection mode.
[0025] A seventh aspect of the invention relates to a fuel injection control apparatus for
a direct injection internal combustion engine, which, when the engine is cold, switches
a fuel injection mode between a batch injection in which fuel is injected once during
an intake stroke and a split injection in which fuel is injected a plurality of times
during the intake stroke, and which is provided with increase correcting means for
setting a fuel increase amount larger for the batch injection than for the split injection
when increase-correcting a fuel injection quantity set based on an engine operating
state.
[0026] As described above, when the engine is cold fuel that is injected does not sufficiently
vaporize. As a result, some of fuel tends to adhere to the inside wall of the combustion
chamber. When fuel is injected during the intake stroke, however, even if fuel were
to adhere, it is highly likely that that adhered fuel would vaporize within the period
of time between fuel injection and ignition. In fact, during the intake stroke fuel
tends to vaporize better when it is split up and injected over a series of separate
injections than when it is injected all at once. Therefore the amount of fuel that
does not contribute to engine combustion is greater in a batch injection than it is
in a split injection.
[0027] In view of this, with the structure according to the seventh aspect of the invention,
when increase-correcting the fuel injection quantity that is set based on the operating
state of the engine, the fuel increase amount is set larger for a batch injection
than it is for a split injection. As a result, even if the injected fuel does not
vaporize as readily in a batch injection, and as a result, the amount of fuel that
does not contribute to combustion increases, a substantive insufficiency in the fuel
injection quantity due to that increase, and thus deterioration of the combustion
state due to that insufficiency, is able to be inhibited.
[0028] According to an eighth aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to the seventh aspect
of the invention, the increase correcting means sets the fuel increase amount based
on at least one of an engine temperature and a time elapsed after engine start-up.
[0029] Injected fuel tends to vaporize more readily the higher the engine temperature and
the temperature of the engine combustion chamber increases over time after the engine
is started. Accordingly, vaporization of injected fuel tends to be promoted the more
time that passes after start-up.
[0030] Regarding this, with the structure according to the eighth aspect of the invention,
when increase-correcting the fuel injection quantity so that the fuel increase amount
is larger for a batch injection than it is for a split injection, the fuel increase
amount can be set according to the extent to which vaporization of injected fuel is
promoted, which changes depending on the engine temperature and the time elapsed after
engine start-up. Accordingly, it is possible to ensure the amount of fuel that actually
contributes to combustion and thus make the combustion state even more stable. The
engine temperature can be estimated based on, for example, the engine coolant temperature
or the engine lubricating oil temperature, just as with the structure according to
the second aspect of the invention.
[0031] According to a ninth aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to the seventh or eighth
aspect of the invention, the increase correction of the fuel injection quantity is
performed when the engine is idling until a predetermined period of time has elapsed
after engine start-up.
[0032] Here, an apparatus is known which increase-corrects the fuel injection quantity while
injecting fuel during the intake stroke when the engine is idling until a predetermined
period of time has elapsed after engine start-up in order to improve the combustion
state. With the structure according to the ninth aspect of the invention, when the
fuel injection mode is switched between batch injection and split injection in such
an apparatus, it is possible to perform a fuel increase of an amount that is appropriate
in view of the extent to which fuel vaporization is promoted and the extent to which
fuel adheres to the combustion chamber wall after engine start-up in each injection
mode.
[0033] A tenth aspect of the invention relates to a fuel injection control apparatus for
a direct injection internal combustion engine, which, after start-up when the engine
is cold, switches a fuel injection mode between a batch injection in which fuel is
injected once and a split injection in which fuel is injected a plurality of times,
wherein when increase-correcting a fuel injection quantity set based on an engine
operating state, from after engine start-up until a predetermined period of time has
passed, the fuel injection mode is set to a first injection mode in which the fuel
increase amount for the split injection is set larger than the fuel increase amount
for the batch injection, and then the fuel injection mode is set to a second injection
mode in which the fuel increase amount for the batch injection is set larger than
the fuel increase amount for the split injection.
[0034] Fuel does not readily vaporize when the engine is cold, and particularly right after
start-up of the internal combustion engine. As a result, fuel adheres to wall surfaces
in the internal combustion engine, i.e., the peripheral walls of the cylinder and
the piston top-surface (hereinafter also simply referred to as "walls"), and it is
highly likely that some of that fuel not contribute to engine combustion and therefore
lead to deterioration of the combustion state. On the other hand, the temperature
in the engine combustion chamber, as well as the temperature of the inside walls of
the engine combustion chamber, gradually increases as time passes after engine start-up,
thereby reducing the possibility that some of the injected fuel will adhere to the
inside wall of the engine combustion chamber and therefore not contribute to engine
combustion. Furthermore, the injected fuel tends to vaporize more readily when it
is injected over a plurality of injections as opposed to when it is injected all at
once.
[0035] In view of this, with the structure according to the tenth aspect of the invention,
the fuel increase amount is set larger for a split injection than it is for a batch
injection from after engine start-up until a predetermined period of time has elapsed.
Then after that, the fuel increase amount is set larger for a batch injection than
it is for a split injection. Accordingly, the fuel increase amount can be set in view
of changes in the extent to which fuel vaporization is promoted and the extent to
which fuel adheres to the cylinder wall after engine start-up, as described above.
Accordingly, it is possible to ensure fuel which contributes to combustion and therefore
improve the stability of engine combustion.
[0036] According to an eleventh aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to the tenth aspect of
the invention, in the first injection mode, fuel is injected once at the end of a
compression stroke in the batch injection while fuel is injected at a plurality of
timings, including at least at the end of the compression stroke, in the split injection,
and in the second injection mode, fuel is injected once during an intake stroke in
the batch injection while fuel is injected a plurality of times during the intake
stroke in the split injection.
[0037] When the engine is cold the injected fuel does not sufficiently vaporize and there
is a tendency for some of the fuel to adhere to the inside wall of the combustion
chamber. Also, when the piston is on the top-dead-center (TDC) side, as it is at the
end of the compression stroke, the exposed area of wall inside the combustion chamber
is small so fuel adherence is inhibited somewhat. On the other hand, however, when
fuel is injected at a time other than at the end of the compression stroke, such as
at the beginning of the compression stroke, the amount of fuel adherence increases,
reducing the percentage of injected fuel that actually contributes to engine combustion.
However, when fuel is injected during the intake stroke, even if fuel were to adhere,
it is highly likely that that adhered fuel would vaporize within the period of time
between fuel injection and ignition. In fact, during the intake stroke fuel tends
to vaporize more readily when it is split up and injected over a series of separate
injections than when it is injected all at once. Therefore the amount of fuel that
does not contribute to engine combustion is greater in a batch injection than it is
in a split injection.
[0038] Regarding this, with the structure according to the eleventh aspect of the invention,
it is possible to set the fuel increase amount according to the extent to which vaporization
of injected fuel is promoted and the extent to which fuel adheres to the walls, which
changes depending on the timing of the injection of the batch injection and the timings
of the injections of the split injection.
[0039] According to the twelfth aspect of the invention, in the fuel injection control apparatus
for a direct injection internal combustion engine according to the tenth or eleventh
aspect of the invention, the fuel increase amount is set based on at least one of
an engine temperature and a time elapsed after engine start-up.
[0040] The amount of fuel that adheres to the inside wall of the engine combustion chamber
tends to increase the lower the engine temperature, and the temperature of the combustion
chamber is lower the less time that has elapsed after engine start-up. Accordingly,
the amount of fuel that adheres to the inside wall of the combustion chamber tends
to increase when that elapsed time is short.
[0041] Regarding this, with the structure according to the twelfth aspect of the invention,
when the fuel injection quantity is increase-corrected so that the fuel increase amount
is larger for a split injection than it is for a batch injection, that fuel increase
amount can be set in view of the fuel adhering amount which changes in response to
the engine temperature or the time that has elapsed after engine start-up. Accordingly,
it is possible to ensure the amount of fuel that actually contributes to combustion
and thus further stabilize the combustion state. The engine temperature can be estimated
based on, for example, the engine coolant temperature or the engine lubricating oil
temperature.
[0042] According to a thirteenth aspect of the invention, the fuel injection control apparatus
for a direct injection internal combustion engine according to any one of the tenth
to the twelfth aspects of the invention further includes split rate setting means
for setting an injection quantity split rate of each injection when the fuel injection
mode is set to the split injection. Further, the split rate setting means sets the
injection quantity split rate of each injection such that the difference between the
injection quantity split rates becomes less the smaller the total quantity of fuel
injected by all of the injections of the split injection.
[0043] Typically, when the target fuel injection quantity is small, i.e., when the total
quantity of fuel to be injected by all of the injections in a split injection is small,
the operational response of the fuel injection valve must be extremely fast because
the interval between the time that the fuel injection valve is open and the time that
it is closed is short. As a result, if the fuel injection quantity of any of the injections
is set too small, the fuel injection may not be able to be performed properly due
to a limit in the operational response of the fuel injection valve. However, when
the target fuel injection quantity is large, i.e., when the total quantity of fuel
to be injected by all of the injections in a split injection is large, the fuel injection
quantity of an injection is less likely to be below the operational response limit
of the fuel injection valve. As a result, there is more freedom when setting the injection
quantity split rates of the injections.
[0044] Regarding this, with the structure according to the thirteenth aspect of the invention,
when the total quantity of fuel injected by the injections of the split injection
is small, i.e., when the fuel injection quantity of any of the injections is extremely
small depending on the setting of the injection quantity split rates, the injection
quantity split rates of the injections are set so that the difference between them
is small. Accordingly, it is possible to inhibit, to the greatest extent possible,
the fuel injection quantity of each injection in a split injection from becoming too
small, which makes it possible to ensure proper fuel injection operation in each injection.
Moreover, when the total fuel quantity is large, the injection quantity split rates
of the injections are set so that the difference between them is large, which means
that they can be set with a high degree of freedom.
[0045] According to a fourteenth aspect of the invention, in the fuel injection control
apparatus for a direct injection internal combustion engine according to the thirteenth
aspect of the invention, the split rate setting means sets the injection quantity
split rate of each injection such that the injection quantity split rates become equal
when the total quantity of fuel injected by all of the injections of the split injection
is equal to, or less than, a predetermined quantity.
[0046] With this structure, when the total quantity of fuel to be injected by all of the
injections of a split injection is equal to, or less than, a predetermined value,
i.e., when the total fuel injection quantity is split unevenly and the fuel injection
quantity of an injection may fall below the minimum fuel injection quantity of the
fuel injection valve, the injection quantity split rates of the injections are set
to be equal. It is therefore possible to avoid, to the greatest extent possible, a
situation occurring in which normal injection is no longer possible due to a fuel
injection quantity of one of the injections of a split injection falling below the
minimum fuel injection quantity of the fuel injection valve. As a result, split injections
can be executed more often.
[0047] The method for setting the injection quantity split rates described in the thirteenth
or fourteenth aspect of the invention is particularly effective when fuel injection
mode is set to the first injection mode, but may also be employed when the fuel injection
mode is set to the second injection mode or regardless of which mode the fuel injection
mode is set to.
[0048] According to the fifteenth aspect of the invention, in the fuel injection control
apparatus for a direct injection internal combustion engine according to any one of
the tenth to the fourteenth aspects of the invention, the increase correction of the
fuel injection quantity is performed when the engine is idling until a predetermined
period of time has elapsed after engine start-up.
[0049] Here, an apparatus is known which increase-corrects the fuel injection quantity when
the engine is idling until a predetermined period of time has elapsed after engine
start-up in order to raise the exhaust gas temperature and improve the combustion
state. With the structure according to the fifteenth aspect of the invention, when
the fuel injection mode is switched between batch injection and split injection in
such an apparatus, a fuel increase can be performed of an amount that is appropriate
in view of the extent to which fuel adheres to the walls and the extent to which fuel
vaporizes in each injection mode.
[0050] A sixteenth aspect of the invention relates to a fuel injection control method for
a direct injection internal combustion engine, which, when the engine is cold, switches
a fuel injection mode between a batch injection in which fuel is injected once at
the end of a compression stroke and a split injection in which fuel is injected at
a plurality of timings including at least at the end of the compression stroke. In
this method, a fuel increase amount is set larger for the split injection than for
the batch injection when increase-correcting a fuel injection quantity set based on
an engine operating state.
[0051] A seventeenth aspect of the invention relates to a fuel injection control method
for a direct injection internal combustion engine, which, when the engine is cold,
switches a fuel injection mode between a batch injection in which fuel is injected
once during an intake stroke and a split injection in which fuel is injected a plurality
of times during the intake stroke. In this method, a fuel increase amount is set larger
for the batch injection than for the split injection when increase-correcting a fuel
injection quantify set based on an engine operating state.
[0052] An eighteenth aspect of the invention relates to a fuel injection control method
for a direct injection internal combustion engine, which, after start-up when the
engine is cold, switches a fuel injection mode between a batch injection in which
fuel is injected once and a split injection in which fuel is injected a plurality
of times. In this method, when increase-correcting a fuel injection quantity set based
on an engine operating state, from after engine start-up until a predetermined period
of time has passed, the fuel injection mode is set to a first injection mode in which
the fuel increase amount for the split injection is set larger than the fuel increase
amount for the batch injection, and then the fuel injection mode is set to a second
injection mode in which the fuel increase amount for the batch injection is set larger
than the fuel increase amount for the split injection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] The foregoing and/or further objects, features and advantages of the invention will
become more apparent from the following description of preferred embodiment with reference
to the accompanying drawings, in which like numerals are used to represent like elements
and wherein:
FIG. 1 is a block diagram schematically showing a concrete fuel injection control
apparatus for an internal combustion engine according to one exemplary embodiment
of the invention;
FIG. 2 is a flowchart illustrating the order of specific steps in a target injection
quantity calculation routine;
FIG. 3 is a flowchart illustrating the order of specific steps in an increase correction
amount calculation routine;
FIG. 4 is a schematic illustration of a map A used for calculating a base increase
amount value;
FIG. 5 is a schematic illustration of a map C used for calculating an injection amount
split rate;
FIG. 6 is a timing chart showing one example of a manner in which an increase correction
amount is calculated;
FIG. 7 is a flowchart illustrating the order of specific steps in an increase correction
coefficient calculation routine;
FIG. 8 is a schematic illustration of maps used for calculating the increase correction
coefficient; and
FIG. 9 is a timing chart illustrating one example of a manner in which a target injection
amount is calculated in control to improve combustion.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0054] Hereinafter, a specific fuel injection control apparatus for an internal combustion
engine according to one exemplary embodiment of the invention will be described. As
shown in FIG. 1, an internal combustion engine 10 to which this exemplary embodiment
can be applied is largely constructed of an intake passage 11, a combustion chamber
12, and an exhaust passage 13. A throttle valve 14 is arranged in the intake passage
11 and a spark plug 15 and an injection valve 16 are arranged in the combustion chamber
12. Further, an exhaust gas control catalyst 17 is provided in the exhaust passage
13.
[0055] When the internal combustion engine 10 is operating, air drawn in from outside is
introduced into the combustion chamber 12 through the intake passage 11. The amount
of air introduced into the combustion chamber 12 is adjusted by controlling the opening
amount of the throttle valve 14.
[0056] Fuel from the fuel injection valve 16 is introduced directly into the combustion
chamber 12, where it is mixed with the air introduced from the intake passage 11.
This mixture of fuel and air is then ignited by a spark discharge from the spark plug
15, upon which the mixture is combusted. Exhaust gas generated from the combustion
is then discharged into the exhaust passage 13 where it is purified by the exhaust
gas control catalyst 17.
[0057] Fuel injection control in the internal combustion engine 10 is performed by an electronic
control unit (hereinafter, simply referred to as "ECU") 20. This ECU 20 includes,
for example, a central computing and processing unit which executes various routines
related to engine control, memory for storing programs for engine control and information
necessary for such control, an input port into which signals from other components
are input, and an output port for outputting signals to other components.
[0058] Various kinds of sensors for detecting the operating state of the engine are connected
to the input port of the ECU 20. Some specific examples of these sensors include an
engine speed sensor for detecting a rotation speed of an engine output shaft (i.e.,
engine speed NE), an acceleration sensor for detecting an operating amount of an accelerator
pedal (i.e., an accelerator operating amount AC), a coolant temperature sensor for
detecting the temperature of engine coolant (i.e., coolant temperature THW), and an
intake amount sensor for detecting an intake air amount GA. In addition, an ignition
switch that is operated when the internal combustion engine 10 is started and the
like is also connected to the input port of the ECU 20. Further, the spark plug 15
and fuel injection valve 16 and the like are connected to the output port of the ECU
20.
[0059] The ECU 20 performs fuel injection control in which it calculates a target injection
quantity Qop based on the operating state of the engine (more specifically, based
on the engine speed NE, the intake air amount GA, the accelerator operating amount
AC, the coolant temperature THW, and the like), and drives the fuel injection valve
16 in accordance with that target injection quantity Qop. As a result, fuel of an
amount appropriate for the operating state of the engine at that time is injected.
Also, in conjunction with setting the target injection quantity Qop, the ECU 20 also
adjusts the intake air amount GA and the ignition timing from the spark plug 15 so
as to obtain the optimum combustion state.
[0060] With the fuel injection control when the engine is cold, control for rapidly warming
up the exhaust gas control catalyst 17 (i.e., catalyst rapid warm-up control) is performed
so as to initiate exhaust gas purification early on. In addition, control for improving
the combustion state (i.e., combustion improvement control) is also executed.
[0061] Hereinafter, the catalyst rapid warm-up control and combustion improvement control
will be described separately, with the catalyst rapid warm-up control being described
first. This catalyst rapid warm-up control is executed when the all of the following
conditions have been satisfied.
- Start-up of the internal combustion engine 10 is complete and the internal combustion
engine 10 is running under its own power.
- The coolant temperature THW at the beginning of start-up of the internal combustion
engine 10 is low.
- The internal combustion engine 10 is idling.
[0062] Catalyst rapid warm-up control aims to improve early activation of the exhaust gas
control catalyst 17 by raising the exhaust gas temperature by performing a fuel injection
at the end of the compression stroke, increasing the intake air amount GA, increasing
the fuel injection quantity, and retarding the ignition timing. The reason for injecting
fuel at the end of the compression stroke is to achieve so-called stratified-charge
combustion, or engine combustion in which a rich flammable mixture is unevenly distributed
near the spark plug 15. By performing stratified-charge combustion it is possible
to significantly retard the ignition timing and greatly increase the intake air amount
GA compared with when homogeneous combustion, which will be described later, is performed.
As a result, the exhaust gas temperature can be set extremely high.
[0063] If too much fuel is injected at the end of the compression stroke, the air-fuel ratio
around the spark plug 15 becomes excessively rich, which results in the deterioration
of the combustion state of the mixture. In this case, therefore, the fuel is split
up and injected over a plurality of injections so that the air-fuel ratio around the
spark plug 15 is suitable. With this kind of fuel injection (i.e., a split injection),
the split may be such that the fuel is injected twice: once at the beginning of the
compression stroke (i.e., 180° BTDC) and once at the end of the compression stroke
(i.e., 30° BTDC), for example.
[0064] Typically, when the fuel injection quantity is small, i.e., when the total quantity
of fuel to be injected over the plurality of injections in a split injection is small,
the interval between the time when the fuel injection valve 16 is open and when it
is closed is short, which means that the fuel injection valve 16 must be highly responsive.
Thus, if the fuel injection quantity is split, there is a possibility that the split
fuel quantity may be less than the minimum fuel injection quantity of the fuel injection
valve 16 (more specifically, less than the injection quantity lower limit which is
determined by the limit in the operational response of the fuel injection valve 16),
making it no longer possible to adjust the injection quantity. Accordingly in this
case, the injection is performed only once (i.e., a batch injection), with fuel being
injected at the end of the compression stroke (e.g., at 25° BTDC). A batch injection
can also be performed when the air-fuel ratio around the spark plug 15 can be made
appropriate, even if all of the fuel is injected at the end of the compression stroke.
[0065] The determination as to whether to perform a split injection or a batch injection
is fundamentally made based upon the total quantity of fuel to be injected into one
cylinder during one cycle (a sequence including an intake stroke, a compression stroke,
a combustion stroke, and an exhaust stroke) of the internal combustion engine 10.
[0066] Here, when the engine is cold, there is a tendency for injected fuel not to vaporize
sufficiently and adhere to the inside wall of the combustion chamber 12. Also, when
the engine piston (hereinafter simply referred to as "piston") P is on the top-dead-center
(TDC) side, as it is at the end of the compression stroke, the exposed area of the
inside wall of the combustion chamber 12 is small so the adherence of fuel is somewhat
limited. Despite this, however, when fuel is injected at a timing other than at the
end of the compression stroke, such as at the beginning of the compression stroke,
the amount of fuel that adheres to the inside wall of the combustion chamber 12 is
large. As a result, the percentage of injected fuel that actually contributes to engine
combustion decreases.
[0067] Given this, this exemplary embodiment is such that when an increase correction amount
Kc is calculated to increase-correct the fuel injection quantity during catalyst rapid
warm-up control, a larger value is calculated for that increase correction amount
Kc for a split injection than for a batch injection. As a result, the fuel injection
quantity is increased more for a split injection, in which the amount of fuel that
adheres to the inside wall of the combustion chamber 12 increases, than for a batch
injection, which suppresses a substantive fuel injection quantity insufficiency caused
by the increased amount of fuel that adheres.
[0068] Next, the control for improving combustion will be described.
Combustion improving control is executed when the all of the following conditions
have been satisfied.
- Start-up of the internal combustion engine 10 is complete and the internal combustion
engine 10 is running under its own power.
- The coolant temperature THW is low.
- The internal combustion engine 10 is idling.
- Catalyst rapid warm-up control is not being executed.
[0069] Combustion improving control aims to improve the combustion state by compensating
for a lack of fuel vaporization action by increasing the quantity of fuel supplied
for combustion through an increase correction of the fuel injection quantity. During
combustion improvement control, a fuel injection is executed at the intake stroke
of the internal combustion engine 10. In this fuel injection at the intake stroke,
so-called homogeneous combustion, or engine combustion with the fuel evenly dispersed
in the combustion chamber 12, is performed.
[0070] In combustion improvement control as well, the fuel injection mode can be switched
between batch injection and split injection. According to this exemplary embodiment,
for example, in a batch injection, fuel is injected only once at the beginning of
the intake stroke (e.g., 300° BTDC), and in a split injection, fuel is injected twice:
once at the early-middle of the intake stroke (240° BTDC) and once at the end of the
intake stroke (180° BTDC). The regions in which the batch and split injections are
respectively executed are determined by, for example, the intake air amount GA, the
engine speed NE, the coolant temperature THW, and the region appropriate for the fuel
injection mode is then obtained and set based on experimental results, for example.
[0071] Here, as described above, when the engine is cold; the fuel that is injected does
not to vaporize sufficiently and there is a tendency for some of it to adhere to the
inside wall of the combustion chamber 12. When fuel is injected during the intake
stroke, however, even if some of the fuel were to adhere, it is highly likely that
the adhered fuel would vaporize during the period between the time the fuel was injected
and ignition. In fact, vaporization tends to be promoted more when fuel injected during
the intake stroke is split up and injected over a series of separate injections than
when it is injected all at once. Therefore there is more fuel that does not contribute
to engine combustion in a batch injection than there is in a split injection.
[0072] Based on this, according to this exemplary embodiment, when calculating the increase
correction coefficient (hereinafter, simply referred to as the "correction coefficient")
Kb to increase-correct the fuel injection quantity in combustion improvement control,
a larger value is calculated for the correction coefficient Kb with a batch injection
than with a split injection. Accordingly, the fuel injection quantity is increased
more for a batch injection, in which the amount of fuel that does not contribute to
combustion increases due to insufficient vaporization of the injected fuel, than it
is for a split injection, thereby suppressing a substantive insufficiency in the fuel
injection quantity due to the increase in the amount of fuel that does not contribute
to combustion.
[0073] Hereinafter, the routine for calculating the increase correction amount Kc in the
catalyst rapid warm-up control and the routine for calculating the target injection
quantity Qop which includes the routine for calculating the correction coefficient
Kb in combustion improvement control will be described.
[0074] First, the routine for calculating the target injection quantity Qop during execution
of the catalyst rapid warm-up control will be described with reference to the flowcharts
shown in FIGS. 2 and 3. The series of steps shown in the flowchart in FIG. 2 illustrates
the specific process for calculating the target injection quantity Qop. The series
of steps shown in the flowchart in FIG. 3 illustrates the specific process for calculating
the increase correction amount Kc. These routines are executed by the ECU 20 at predetermined
cycles.
[0075] As shown in FIG. 2, when calculating the target injection quantity Qop, a required
injection quantity Qcal is first calculated based on, for example, the engine speed
NE, the intake air amount GA, or the accelerator operating amount AC (i.e., step S100).
Then various correction amounts (i.e., Ki, ...) other than the correction coefficient
Kb and the increase correction amount Kc, such as the correction amount for the intake
air temperature, the correction amount for atmospheric pressure, and the correction
amount for the coolant temperature THW, are calculated (i.e., step S102).
[0076] Because the catalyst rapid warm-up control is being executed at this time (i.e.,
YES in step S104), the routine for calculating the increase correction amount Kc for
the catalyst rapid warm-up control is executed (i.e., step S106).
[0077] As shown in FIG. 3, when calculating the increase correction amount Kc, a base increase
amount value Kcb is first calculated from a map A based on the coolant temperature
THW as the indication value for the engine temperature, and the time elapsed after
the ignition switch has been operated to start the internal combustion engine 10 (i.e.,
time Ts elapsed after start-up) (i.e., step S200).
[0078] For this base increase value Kcb, a value may be calculated which is able to facilitate
early warm-up of the exhaust gas control catalyst 17 while enabling stable operation
of the internal combustion engine 10 when batch injection is selected. The relationship
between that base increase amount value Kcb, and the coolant temperature THW and the
time Ts elapsed after start-up is obtained through experimental results or the like
and set on the map A.
[0079] The amount of fuel that adheres to the inside wall of the combustion chamber 12 tends
to increase the lower the engine temperature. Also, the temperature of the combustion
chamber 12 is lower the closer to start-up (i.e., the less time that has elapsed after
start-up), so there is a tendency for the amount of fuel that adheres to the inside
of the combustion chamber 12 to be greater the shorter that elapsed time. Based on
this, according to this exemplary embodiment, the base increase amount value Kcb is
calculated to be a larger value the lower the coolant temperature THW and the shorter
the time Ts elapsed after start-up, to be specific, as is conceptually shown in map
A in FIG. 4. As a result, it is possible to calculate the increase correction amount
Kc in view of the amount of fuel that adheres, which changes depending on the engine
temperature and the time Ts elapsed after start-up. Accordingly, it becomes possible
to ensure the amount of fuel that actually contributes to combustion.
[0080] Then when batch injection is selected (i.e., NO in step S202 in FIG. 3) the base
increase value Kcb is set as the increase correction amount Kc (i.e., step S204).
When split injection is selected (i.e., YES in step S202), on the other hand, a split
injection correction amount Kc2 is calculated from a map B based on the coolant temperature
THW and the time Ts elapsed time after start-up (i.e., step S206). For this split
injection correction amount Kc2, a value may be calculated that can compensate for
the insufficiency that is due to the split injection being selected, from the fuel
injection quantity insufficiency that is due to the increase in the amount of fuel
that adheres to the inside wall of the combustion chamber 12. The relationship between
that split injection correction amount Kc2, and the coolant temperature THW and the
time Ts elapsed after start-up is obtained through experimental results or the like
and set on map B. The split injection correction amount Kc2 is calculated to be a
larger value the lower the coolant temperature THW and the shorter the time Ts elapsed
after start-up, to be specific.
[0081] For the increase correction amount Kc, a value which is the sum of the base increase
amount value Kcb and the split injection correction amount Kc2 (i.e., Kcb + Kc2) is
calculated (i.e., step S208). Further, an injection quantity split rate Rt for the
first fuel injection is calculated from a map C based on the coolant temperature THW
(i.e., step S210). Hereinafter, the manner in which the injection quantity split rate
Rt is calculated will be described with reference to FIG. 5 which conceptually shows
map C.
[0082] As shown in FIG. 5, when the coolant temperature THW is equal to, or greater than,
a predetermined temperature THb, the injection amount split rate Rt is calculated
to be 0.5. At this time, when the total quantity of fuel to be injected over the injections
is small and the total fuel injection quantity is split unequally, a situation may
occur in which the fuel injection quantity of either injection falls below the minimum
fuel injection quantity of the fuel injection valve 16 such that normal injection
is no longer possible. Therefore, the injection quantity split rate Rt is set so that
the injection quantity split rates of the injections are equal. As a result, the foregoing
situation can be avoided to the greatest extent possible, and split injections can
be executed more often.
[0083] Meanwhile, when the coolant temperature THW is lower than the predetermined temperature
THb but higher than a predetermined temperature THa, the injection quantity split
rate Rt is calculated to be a value that is smaller than 0.5 but which approaches
0.5 the higher the coolant temperature THW becomes.
[0084] At this time, the total quantity of fuel to be injected from both injections is relatively
small, and depending on the settings of the injection quantity split rates, the fuel
injection quantity of one injection or the other may be too small. The injection quantity
split rate Rt is therefore set so that the difference between the injection quantity
split rates of the injections is relatively small. Accordingly it is possible to suppress,
to the greatest extent possible, the fuel injection quantity of each injection in
a split injection from becoming too small, and therefore possible to ensure proper
fuel injection operation in each injection. Also at this time, the injection quantity
split rate Rt is set such that the fuel injection quantity of the second injection
(i.e., at the end of the compression stroke) in a split injection is greater than
the fuel injection quantity of the first injection (i.e., at the beginning of the
compression stroke), which enables stratified-charge combustion to be performed relatively
stably.
[0085] On the other hand, when the coolant temperature THW is equal to, or less than, the
predetermined temperature THa, the injection quantity split rate Rt is calculated
to be a predetermined value (such as 0.3). At this time, the total quantity of fuel
to be injected by both injections is large and there is a high degree of freedom when
setting the injection quantity split rates of the injections of a split injection.
Therefore, the injection quantity split rate Rt is calculated to be a predetermined
value that enables stratified-charge engine combustion to be performed stably. This
predetermined value is obtained and set base on experimental results or the like.
[0086] After the increase correction amount Kc and the injection quantity split rate Rt
have been calculated as described above, this cycle of the routine for calculating
the increase correction amount Kc for the catalyst rapid warm-up control ends. Then
as shown in FIG. 2, in the step for calculating the target injection quantity Qop,
since combustion improvement control is not being executed at this time (i.e., NO
in step S108), the correction coefficient Kb is calculated as a value of 1.0 which
does not increase-correct the fuel injection quantity (i.e., step S110).
[0087] The target injection quantity Qop is calculated from the following expression (1)
based on the required injection quantity Qcal, the various correction amounts Ki ...,
the increase correction amount Kc, and the correction coefficient Kb (i.e., step S
112).

When a batch injection is selected (i.e., NO in step S114), the fuel injection valve
16 is driven according to the target injection quantity Qop and the fuel injection
quantity is adjusted.
[0088] When a split injection is selected (i.e., YES in step S114), on the other hand, target
injection quantities Qop1 and Qop2 for the two injections are both calculated from
the following expressions (2) and (3) based on the target injection quantity Qop and
the injection quantity split rate Rt (i.e., step S116).

The fuel injection valve 16 is then driven and the fuel injection quantity for the
first injection is then adjusted in accordance with the first injection quantity Qop1
for the first injection (i.e., at the beginning of the compression stroke). Similarly,
the fuel injection valve 16 is driven and the fuel injection quantity for the second
injection is adjusted in accordance with the second injection quantity Qop2 for the
second injection (i.e., at the end of the compression stroke).
[0089] In this exemplary embodiment, the fuel injection mode in the catalyst rapid warm-up
control described above corresponds to a first injection mode in which the fuel increase
amount from after engine start-up until after a predetermined period of time has passed
is set larger for a split injection than it is for a batch injection. The predetermined
period of time in this case is a period of time for which the catalyst rapid warm-up
control is executed, and is set based on the engine temperature. More specifically,
this predetermined period of time is set longer the lower the engine temperature at
engine start-up. The predetermined period of time is set in this way because there
is a greater possibility of the outside air temperature being low the lower the engine
temperature, which means that more time is required to warm up the exhaust gas control
catalyst 17.
[0090] FIG. 6 shows one example of a manner in which the increase correction amount Kc is
calculated when the injection mode is switched between split injection and batch injection
while catalyst rapid warm-up control is being executed. As shown in the drawing, the
increase correction amount Kc when a split injection is selected (i.e., before time
t10) is calculated to be a value which is larger than the increase correction amount
Kc when a batch injection is selected by an amount corresponding to the split injection
correction value Kc2. Therefore, even if the amount of fuel that adheres to the inside
wall of the combustion chamber 12 increases when a split injection is selected, a
substantive insufficiency in the fuel injection quantity due to that increase, and
thus deterioration of the combustion state due to that insufficiency, is able to be
inhibited. As a result, it is possible to achieve both stable operation of the internal
combustion engine 10 and early warm-up of the exhaust gas control catalyst 17 when
either a split injection or a batch injection (after time t10) is selected.
[0091] Next, the process for calculating the target injection quantity Qop when combustion
improvement control is executed will be described with reference to the flowcharts
shown in FIGS. 2 and 7. The series of steps shown in the flowchart in FIG. 7 illustrates
a specific routine for calculating the correction coefficient Kb, which is executed
by the ECU 20 at predetermined cycles.
[0092] As shown in FIG. 2, when the target injection quantity Qop is calculated, the required
injection quantity Qcal is first calculated (i.e., step S100) and the various correction
amounts (Ki, ...) are calculated (i.e., step S102). Because catalyst rapid warm-up
control is not being executed at this time (i.e., NO in step S104), the increase correction
amount Kc is set to a value that does not increase-correct the fuel injection quantity
(more specifically, a value of 0) (i.e., step S118). Also, the injection quantity
split rate Rt is set at a value of 0.5 at this time.
[0093] Then, because combustion improvement control is being executed at this time (i.e.,
YES in step S108), a routine to calculate the correction coefficient Kb for combustion
improvement control is executed (i.e., step S120).
[0094] More specifically, as shown in FIG. 7, when a split injection is selected (i.e.,
YES in step S300), the correction coefficient Kb is calculated from a map D based
on the coolant temperature THW and an engine load ratio KL (= GA / NE) (i.e., step
S302). When a batch injection is selected (i.e., NO in step S300), on the other hand,
the correction coefficient Kb is calculated from a map E based on the coolant temperature
THW and the engine load ratio KL (i.e., step S304).
[0095] Map D and map E are both maps for calculating the correction coefficient Kb as a
value that is able to improve the combustion state while maintaining stable operation
of the internal combustion engine 10. The relationship between the correction coefficient
Kb, and the coolant temperature THW and the engine load ratio KL is obtained through
experimental results or the like and then set on each of the maps.
[0096] Here, because injected fuel tends to vaporize more readily the higher the engine
temperature, the amount of fuel that actually contributes to combustion is also greater.
Further, because the fuel injection quantity is adjusted to be greater the higher
the engine load ratio KL, the amount of fuel that contributes to combustion increases.
[0097] Therefore, in this exemplary embodiment, the correction coefficient Kb is calculated
to be a smaller value the higher the coolant temperature THW as well as when the engine
load ratio KL is large, as maps D and E conceptually show in FIG. 8. As a result,
it is possible to calculate the correction coefficient Kb in view of the fuel adhering
amount which changes depending on the engine load ratio KL and the degree to which
vaporization of the injected fuel is promoted, which in turn changes depending on
the engine temperature. Accordingly, it becomes possible to ensure the amount of fuel
that actually contributes to combustion.
[0098] However, map D and map E are set such that the correction coefficient Kb that is
calculated from map D is a smaller value than the correction coefficient Kb that is
calculated from map E when the coolant temperature THW and the engine load ratio KL
are under the same conditions.
[0099] After the correction coefficient Kb is calculated as described above, the target
injection quantity Qop is calculated from the foregoing relational expression (1)
based on the required injection quantity Qcal, the various correction amounts Ki...,
the increase correction amount Kc, and the correction coefficient Kb, as shown in
FIG. 2.
[0100] When a batch injection is selected (i.e., NO in step S114), the fuel injection valve
16 is driven according to the target injection quantity Qop and the fuel injection
quantity is adjusted. When a split injection is selected (i.e., YES in step S114),
on the other hand, target injection quantities Qop1 and Qop2 for the two injections
are both calculated from the foregoing relational expressions (2) and (3) based on
the target injection quantity Qop and the injection quantity split rate Rt (i.e.,
step S116). The fuel injection valve 16 is then driven according to the target injection
quantities Qop1 and Qop2 and the fuel injection quantities for the two injections
are adjusted.
[0101] In this exemplary embodiment, the fuel injection mode in combustion improvement control
described above corresponds to a second injection mode in which the fuel increase
amount is set larger for a batch injection than it is for a split injection. FIG.
9 shows one example of a manner in which the target injection quantity Qop is calculated
when the injection mode is switched between split injection and batch injection while
combustion improvement control is being executed.
[0102] As shown in FIG. 9, the correction coefficient Kb when a split injection is selected
(i.e., before time t20) is calculated to be a value which is smaller than the correction
coefficient Kb when a batch injection is selected. Accordingly, the correction coefficient
Kb when either the batch injection or the split injection is selected, and thus the
target injection quantity Qop, can be calculated in view of the tendency described
above for the amount of fuel that does not contribute to combustion to be larger with
a batch injection than with a split injection when fuel is injected during the intake
stroke. Therefore, even if the injected fuel does not vaporize as readily when a batch
injection is selected, such that the amount of fuel which does not contribute to combustion
increases, a substantive insufficiency in the fuel injection quantity due to that
increase, and thus deterioration of the combustion state due to that insufficiency,
is able to be inhibited. As a result, it is possible to improve the combustion state
while maintaining stable operation of the internal combustion engine 10 when both
a split injection and a batch injection (after time t20) are selected.
[0103] As described above, the following effects can be obtained with this exemplary embodiment.
- (1) In an increase correction of the fuel injection amount in catalyst rapid warm-up
control, the increase correction amount Kc is calculated as a larger value for a split
injection than it is for a batch injection. Therefore, even if the amount of fuel
that adheres to the inside wall of the combustion chamber 12 increases when a split
injection is performed, a substantive insufficiency in the fuel injection quantity
due to that increase, and thus deterioration of the combustion state due to that insufficiency,
is able to be inhibited.
[0104] (2) The increase correction amount Kc is calculated based on the coolant temperature
THW and the time Ts elapsed after start-up. Therefore, the increase correction amount
Kc can be calculated in view of the fact that amount of fuel that adheres changes
depending on the engine temperature and the time Ts elapsed after start-up, which
makes it possible to ensure the amount of fuel that actually contributes to combustion
and thus further improve the stability of the combustion state.
[0105] (3) With a split injection during catalyst rapid warm-up control, the injection quantity
split rate Rt is calculated to be closer to 0.5 the higher the coolant temperature
THW. Therefore, when the total quantity of fuel to be injected from both injections
is relatively small, the fuel injection quantity of one injection or the other may
be too small depending on the settings of the injection quantity split rates. The
injection quantity split rate Rt is therefore set so that the difference between the
injection quantity split rates of the injections is relatively small. Accordingly
it is possible to suppress, to the greatest extent possible, the fuel injection quantity
of each injection from becoming too small, and thus possible to ensure proper fuel
injection operation in each injection.
[0106] (4) When the coolant temperature THW is equal to, or greater than, the predetermined
temperature THb, the injection quantity split rate Rt is calculated to be 0.5. Therefore,
when the total quantity of fuel to be injected over the injections is small and the
total fuel injection quantity is split unequally, a situation may occur in which the
fuel injection quantity of one injection or the other falls below the minimum fuel
injection quantity of the fuel injection valve 16 such that proper injection is no
longer possible. Therefore, the injection quantity split rate Rt is set so that the
injection quantity split rates of the injections are equal. As a result, the foregoing
situation can be avoided to the greatest extent possible so split injections can be
executed more often.
[0107] (5) When the coolant temperature THW is equal to, or less than, the predetermined
temperature THa, the injection quantity split rate Rt is calculated to be a predetermined
value. As a result, stratified-charge combustion is able to be performed stably.
[0108] (6) When the fuel injection quantity is increase-corrected during combustion improvement
control, the correction coefficient Kb is calculated to be a larger value for a batch
injection than it is for a split injection. Therefore, even if the injected fuel does
not vaporize as readily when a batch injection is performed, such that the amount
of fuel which does not contribute to combustion increases, a substantive insufficiency
in the fuel injection quantity due to that increase, and thus deterioration of the
combustion state due to that insufficiency, is able to be inhibited.
[0109] (7) The correction coefficient Kb is calculated based on the coolant temperature
THW. Therefore, the correction coefficient Kb can be calculated in view of the degree
to which vaporization of the injected fuel is promoted, which changes depending on
the engine temperature. Accordingly, it becomes possible to ensure the amount of fuel
that actually contributes to combustion and thus further stabilize the combustion
state.
[0110] (8) When the fuel injection quantity is increase-corrected while the engine is cold,
the fuel increase is set to be greater for a split injection than it is for a batch
injection when catalyst rapid warm-up control is being executed. Then when combustion
improvement control is being executed, the fuel increase is set to be greater for
a batch injection than it is for a split injection. Accordingly, it is possible to
set the fuel increase in view of changes in the extent to which fuel vaporization
is promoted and the extent to which fuel adheres to the cylinder wall after engine
start-up, as described above. Accordingly, it is possible to ensure fuel which contributes
to combustion and therefore stabilize engine combustion.
[0111] The foregoing exemplary embodiment may be modified as follows.
- Other than the coolant temperature THW, any value that has a high correlation to the
total fuel quantity injected over the injections of a split injection, such as the
engine speed NE, the intake air amount GA, or the time Ts elapsed after start-up,
can be used as a calculation parameter of the injection quantity split rate Rt. In
other words, those parameters can be used as indication values for the total fuel
quantity, and the injection quantity split rates for the injections can be set based
on the total fuel quantity.
[0112] More specifically, the injection quantity split rates of the injections may be set
as in the following three configurations. Configuration 1: The injection quantity
split rates of the injections are set so that the difference between them is less
the smaller the total fuel quantity. Configuration 2: The injection quantity split
rates of the injections are set so that they are equal when the total fuel quantity
is equal to, or less than, a predetermined quantity. Configuration 3: The injection
quantity split rates of the injections are set so that the fuel injection quantity
of the injection at the end of the compression stroke is greater than the fuel injection
quantity of any other injection when the total fuel quantity is equal to, or greater
than, a predetermined quantity.
[0113] - For a split injection during combustion improvement control, the injection quantity
split rates of the injections may be set variably based on the total quantity of fuel
to be injected over the injections. Even with this configuration, effects similar
to those described in sections (3) and (4) above can be obtained by setting the injection
quantity split rates of the injections as they are in configurations 1 and 2 above.
[0114] - In the foregoing exemplary embodiment, the increase correction amount Kc and the
correction coefficient Kb are calculated based on the coolant temperature THW as the
indication value of the engine temperature. Instead of the coolant temperature THW,
however, another value indicative of the engine temperature may be used, such as the
temperature of engine lubricating oil, for example. Also, a temperature sensor may
be provided in the internal combustion engine 10 and the engine temperature detected
by that temperature sensor may be used, for example.
[0115] - The first fuel injection timing in a split injection during catalyst rapid warm-up
control can be changed as appropriate, e.g., in the middle of the compression stroke
or at the end of the intake stroke.
- The second fuel injection timing in a split injection during combustion improvement
control may also be set to be at the beginning of the compression stroke.
[0116] - This invention can also be applied to an apparatus which injects fuel in a series
of separate injections at three or more different timings.
- The invention can also be applied to a fuel injection control apparatus of an internal
combustion engine in which only one of the catalyst rapid warm-up control and the
combustion improvement control is executed. In an apparatus in which only combustion
improvement control is executed, the fuel increase amount may also be calculated based
on the time elapsed after start-up. With this structure, the fuel increase amount
can be set in view of the tendency of the temperature of the engine combustion chamber
to increase, and therefore vaporization of the injected fuel to be promoted, the more
time that elapses after engine start-up. Accordingly, it is possible to ensure the
amount of fuel that actually contributes to combustion, and thus further stabilize
the combustion state.
[0117] - The invention can also be applied to an apparatus which executes so-called post
start-up increase correction control, or control to increase-correct the fuel injection
quantity over a predetermined period of time (such as several tens of seconds) immediately
after start-up is complete in order to compensate for insufficient fuel vaporization
immediately after a cold start of the internal combustion engine.
[0118] While the invention has been described with reference to exemplary embodiments thereof,
it is to be understood that the invention is not limited to the exemplary embodiments
or constructions. To the contrary, the invention is intended to cover various modifications
and equivalent arrangements which are within the scope of the invention described
in the claims.
1. A fuel injection control apparatus for a direct injection internal combustion engine
(10) including an ignition device for igniting an air/fuel mixture, which, when the
engine is cold, switches a fuel injection mode between a batch injection in which
fuel is injected once at the end of a compression stroke and a split injection in
which fuel is injected at a plurality of timings including at least at the end of
the compression stroke, the fuel injection control apparatus characterised by comprising increase correcting means (20) for setting a fuel increase amount larger
for the split injection than for the batch injection when increase-correcting a fuel
injection quantity set based on an engine operating state.
2. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 1, wherein the increase correcting means sets the fuel increase
amount based on at least one of an engine temperature and a time elapsed after engine
start-up.
3. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 1 or 2, further comprising split rate setting means (20) for setting
an injection quantity split rate of each injection when the fuel injection mode is
set to the split injection, wherein the split rate setting means sets the injection
quantity split rate of each injection such that the difference between the injection
quantity split rates becomes less the smaller the total quantity of fuel injected
by all of the injections of the split injection.
4. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 3, wherein the split rate setting means sets the injection quantity
split rate of each injection such that the injection quantity split rates become equal
when the total quantity of fuel injected by all of the injections of the split injection
is equal to, or less than, a predetermined quantity.
5. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 3 or 4, wherein the split rate setting means sets the injection
quantity split rate of each injection such that the fuel injection quantity of the
injection at the end of the compression stroke is larger than the fuel injection quantity
of any other injection when the total quantity of fuel injected by all of the injections
of the split injection is greater than a predetermined value.
6. The fuel injection control apparatus for a direct injection internal combustion engine
according to any one of claims 1 to 5, wherein the increase correction of the fuel
injection quantity is performed when the engine is idling until a predetermined period
of time has elapsed after engine start-up.
7. A fuel injection control apparatus for a direct injection internal combustion engine
(10), including an ignition device for igniting an air/fuel mixture, which, when the
engine is cold, switches a fuel injection mode between a batch injection in which
fuel is injected once during an intake stroke and a split injection in which fuel
is injected a plurality of times during the intake stroke, the fuel injection control
apparatus characterised by comprising increase correcting means (20) for setting a fuel increase amount larger
for the batch injection than for the split injection when increase-correcting a fuel
injection quantity set based on an engine operating state.
8. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 7, wherein the increase correcting means sets the fuel increase
amount based on at least one of an engine temperature and a time elapsed after engine
start-up.
9. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 7 or 8, wherein the increase correction of the fuel injection quantity
is performed when the engine is idling until a predetermined period of time has elapsed
after engine start-up.
10. A fuel injection control apparatus for a direct injection internal combustion engine
(10), including an ignition device for igniting an air/fuel mixture, which, after
start-up when the engine is cold, switches a fuel injection mode between a batch injection
in which fuel is injected once and a split injection in which fuel is injected a plurality
of times, wherein when increase-correcting a fuel injection quantity set based on
an engine operating state, from after engine start-up until a predetermined period
of time has passed, the fuel injection mode is set to a first injection mode in which
the fuel increase amount for the split injection is set larger than the fuel increase
amount for the batch injection, and then the fuel injection mode is set to a second
injection mode in which the fuel increase amount for the batch injection is set larger
than the fuel increase amount for the split injection.
11. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 10, wherein in the first injection mode, fuel is injected once
in the batch injection while fuel is injected at a plurality of timings, including
at least at the end of a compression stroke, in the split injection, and in the second
injection mode, fuel is injected once during an intake stroke in the batch injection
while fuel is injected a plurality of times during the intake stroke in the split
injection.
12. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 10 or 11, wherein the fuel increase amount is set based on at least
one of an engine temperature and a time elapsed after engine start-up.
13. The fuel injection control apparatus for a direct injection internal combustion engine
according to any one of claims 10 to 12, further comprising split rate setting means
(20) for setting an injection quantity split rate of each injection when the fuel
injection mode is set to the split injection, wherein the split rate setting means
sets the injection quantity split rate of each injection such that the difference
between the injection quantity split rates becomes less the smaller the total quantity
of fuel injected by all of the injections of the split injection.
14. The fuel injection control apparatus for a direct injection internal combustion engine
according to claim 13, wherein the split rate setting means sets the injection quantity
split rate of each injection such that the injection quantity split rates become equal
when the total quantity of fuel injected by all of the injections of the split injection
is equal to, or less than, a predetermined quantity.
15. The fuel injection control apparatus for a direct injection internal combustion engine
according to any one of claims 10 to 14, wherein the increase correction of the fuel
injection quantity is performed when the engine is idling until a predetermined period
of time has elapsed after engine start-up.
16. A fuel injection control method for a direct injection internal combustion engine
(10) including an ignition device for igniting an air/fuel mixture, which, when the
engine is cold, switches a fuel injection mode between a batch injection in which
fuel is injected once at the end of a compression stroke and a split injection in
which fuel is injected at a plurality of timings including at least at the end of
the compression stroke, the fuel injection control method
characterised by comprising:
setting a fuel increase amount larger for the split injection than for the batch injection
when increase-correcting a fuel injection quantity set based on an engine operating
state.
17. A fuel injection control method for a direct injection internal combustion engine
(10), including an ignition device for igniting an air/fuel mixture, which, when the
engine is cold, switches a fuel injection mode between a batch injection in which
fuel is injected once during an intake stroke and a split injection in which fuel
is injected a plurality of times during the intake stroke, the fuel injection control
method
characterised by comprising:
setting a fuel increase amount larger for the batch injection than for the split injection
when increase-correcting a fuel injection quantity set based on an engine operating
state.
18. A fuel injection control method for a direct injection internal combustion engine
(10), including an ignition device for igniting an air/fuel mixture, which, after
start-up when the engine is cold, switches a fuel injection mode between a batch injection
in which fuel is injected once and a split injection in which fuel is injected a plurality
of times, the fuel injection control method
characterized in that:
when increase-correcting a fuel injection quantity set based on an engine operating
state, from after engine start-up until a predetermined period of time has passed,
the fuel injection mode is set to a first injection mode in which the fuel increase
amount for the split injection is set larger than the fuel increase amount for the
batch injection, and then the fuel injection mode is set to a second injection mode
in which the fuel increase amount for the batch injection is set larger than the fuel
increase amount for the split injection.
1. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
(10) mit einer Zündvorrichtung zum Zünden eines Luft-KraftstoffGemisches, welche,
wenn die Maschine kalt ist, einen Kraftstoffeinspritzmodus zwischen einer Ladungseinspritzung
(batch injection), bei welcher Kraftstoff einmal am Ende eines Verdichtungshubs eingespritzt
wird, und einer Aufteilungseinspritzung (split injection), bei welcher Kraftstoff
an einer Vielzahl von Zeitpunkten einschließlich zumindest am Ende des Verdichtungshubs
eingespritzt wird, schaltet,
gekennzeichnet durch:
eine Erhöhungskorrektureinrichtung (20), um für die Aufteilungseinspritzung einen
größeren Kraftstofferhöhungsbetrag als für die Ladungseinspritzung einzustellen, wenn
eine Erhöhungskorrektur einer auf der Basis eines Betriebszustandes der Maschine festgelegten
Kraftstoffeinspritzmenge durchgeführt wird.
2. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 1, wobei die Erhöhungskorrektureinrichtung den Kraftstofferhöhungsbetrag
wenigstens auf der Basis einer Maschinentemperatur und/oder einer seit dem Start der
Maschine verstrichenen Zeitdauer einstellt.
3. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 1 oder 2, welche ferner eine Aufteilungsraten-Einstelleinrichtung (20)
zum Einstellen einer Kraftstoffmengen-Aufteilungsrate jeder Einspritzung, wenn der
Kraftstoffeinspritzmodus auf die Aufteilungseinspritzung gesetzt wird, aufweist, wobei
die Aufteilungsraten-Einstelleinrichtung die Einspritzmengen-Aufteilungsrate jeder
Einspritzung so einstellt, dass die Differenz zwischen der Einspritzmengen-Aufteilungsrate
um so geringer wird, je kleiner die Gesamtmenge des durch alle Einspritzungen der
Aufteilungseinspritzung eingespritzten Kraftstoffs ist.
4. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 3, wobei die Aufteilungsraten-Einstelleinrichtung die Einspritzmengen-Aufteilungsrate
jeder Einspritzung so einstellt, dass die Einspritzmengen-Aufteilungsraten gleich
werden, wenn die Gesamtmenge des durch alle Einspritzungen der Aufteilungseinspritzung
eingespritzten Kraftstoffs gleich oder weniger als eine vorbestimmte Menge ist.
5. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 3 oder 4, wobei die Aufteilungsraten-Einstelleinrichtung die Einspritzmengen-Aufteilungsrate
jeder Einspritzung so einstellt, dass die Kraftstoffeinspritzmenge der Einspritzung
am Ende des Verdichtungshubs größer ist als die Kraftstoffeinspritzmenge jeder anderen
Einspritzung, wenn die Gesamtmenge des durch alle Einspritzungen der Aufteilungseinspritzung
eingespritzten Kraftstoffs größer als ein vorbestimmter Wert ist.
6. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß einem der Ansprüche 1 bis 5, wobei die Erhöhungskorrektur der Kraftstoffeinspritzmenge
durchgeführt wird, wenn sich die Maschine im Leerlauf befindet, und zwar bis eine
vorbestimmte Zeitdauer seit dem Start der Maschine verstrichen ist.
7. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
(10) mit einer Zündvorrichtung zum Zünden eines Luft-KraftstoffGemisches, welche,
wenn die Maschine kalt ist, einen Kraftstoffeinspritzmodus zwischen einer Ladungseinspritzung
(batch injection), bei welcher Kraftstoff einmal während eines Ansaughubs eingespritzt
wird, und einer Aufteilungseinspritzung (split injection), bei welcher Kraftstoff
mehrmals während des Ansaughubs eingespritzt wird, schaltet,
gekennzeichnet durch:
eine Erhöhungskorrektureinrichtung (20), um für die Ladungseinspritzung einen größeren
Kraftstofferhöhungsbetrag als für die Aufteilungseinspritzung einzustellen, wenn eine
Erhöhungskorrektur einer auf der Basis eines Betriebszustandes der Maschine festgelegten
Kraftstoffeinspritzmenge durchgeführt wird.
8. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 7, wobei die Erhöhungskorrektureinrichtung den Kraftstofferhöhungsbetrag
wenigstens auf der Basis einer Maschinentemperatur und/oder einer seit dem Start der
Maschine verstrichenen Zeitdauer einstellt.
9. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 7 oder 8, wobei die Erhöhungskorrektur der Kraftstoffeinspritzmenge
durchgeführt wird, wenn sich die Maschine im Leerlauf befindet, und zwar bis eine
vorbestimmte Zeitdauer seit dem Start der Maschine verstrichen ist.
10. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
(10) mit einer Zündvorrichtung zum Zünden eines Luft-KraftstoffGemisches, welche nach
dem Start, wenn die Maschine kalt ist, einen Kraftstoffeinspritzmodus zwischen einer
Ladungseinspritzung (batch injection), bei welcher Kraftstoff einmal eingespritzt
wird, und einer Aufteilungseinspritzung (split injection), bei welcher Kraftstoff
mehrmals eingespritzt wird, schaltet, wobei, wenn eine Erhöhungskorrektur einer auf
der Basis eines Betriebszustandes der Maschine festgelegten Kraftstoffeinspritzmenge
durchgeführt wird, vom Start der Maschine bis zu einer vorbestimmten verstrichenen
Zeitdauer der Kraftstoffeinspritzmodus auf einen ersten Einspritzmodus gesetzt wird,
bei welchem für die Aufteilungseinspritzung ein größerer Kraftstofferhöhungsbetrag
als für die Ladungseinspritzung eingestellt wird, und anschließend der Kraftstoffeinspritzmodus
auf einen zweiten Einspritzmodus gesetzt wird, bei welchem für die Ladungseinspritzung
ein größerer Kraftstofferhöhungsbetrag als für die Aufteilungseinspritzung einstellt
wird.
11. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 10, wobei in dem ersten Einspritzmodus bei der Ladungseinspritzung
Kraftstoff einmal eingespritzt wird, während bei der Aufteilungseinspritzung Kraftstoff
an einer Vielzahl von Zeitpunkten einschließlich wenigstens dem Ende eines Verdichtungshubs
eingespritzt wird, und in dem zweiten Einspritzmodus bei der Ladungseinspritzung Kraftstoff
einmal während eines Ansaughubs eingespritzt wird, während bei der Aufteilungseinspritzung
der Kraftstoff mehrmals während des Ansaughubs eingespritzt wird.
12. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 10 oder 11, wobei der Kraftstofferhöhungsbetrag wenigstens auf der
Basis einer Maschinentemperatur und/oder seit dem Start der Maschine verstrichenen
Zeitdauer eingestellt wird.
13. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß einem der Ansprüche 10 bis 12, welcher ferner eine Aufteilungsraten-Einstelleinrichtung
(20) aufweist, um eine Einspritzmengen-Aufteilungsrate jeder Einspritzung einzustellen,
wenn der Kraftstoffeinspritzmodus auf die Aufteilungseinspritzung gesetzt wird, wobei
die Aufteilungsraten-Einstelleinrichtung die Einspritzmengen-Aufteilungsrate jeder
Einspritzung so einstellt, dass die Differenz zwischen der Einspritzmengen-Aufteilungsrate
um so geringer wird, je kleiner die Gesamtmenge des durch alle Einspritzungen der
Aufteilungseinspritzung eingespritzten Kraftstoffs ist.
14. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß Anspruch 13, wobei die Aufteilungsraten-Einstelleinrichtung die Einspritzmengen-Aufteilungsrate
jeder Einspritzung so einstellt, dass die Einspritzmengen-Aufteilungsraten gleich
werden, wenn die Gesamtmenge des durch alle Einspritzungen der Aufteilungseinspritzung
eingespritzten Kraftstoffs gleich oder geringer als eine vorbestimmte Menge wird.
15. Kraftstoffeinspritzung-Steuervorrichtung für eine Brennkraftmaschine mit Direkteinspritzung
gemäß einem der Ansprüche 10 bis 14, wobei die Erhöhungskorrektur der Kraftstoffeinspritzmenge
durchgeführt wird, wenn sich die Maschine im Leerlauf befindet, und zwar bis eine
vorbestimmte Zeitdauer seit dem Start der Maschine verstrichen ist.
16. Kraftstoffeinspritzung-Steuerverfahren für eine Brennkraftmaschine mit Direkteinspritzung
(10) mit einer Zündvorrichtung zum Zünden eines Luft-KraftstoffGemisches, welche,
wenn die Maschine kalt ist, einen Kraftstoffeinspritzmodus zwischen einer Ladungseinspritzung
(batch injection), bei welcher Kraftstoff einmal am Ende eines Verdichtungshubs eingespritzt
wird, und einer Aufteilungseinspritzung (split injection), bei welcher Kraftstoff
an einer Vielzahl von Zeitpunkten einschließlich zumindest am Ende des Verdichtungshubs
eingespritzt wird, schaltet,
gekennzeichnet durch:
Einstellen eines größeren Kraftstofferhöhungsbetrages für die Aufteilungseinspritzung
als für die Ladungseinspritzung, wenn eine Erhöhungskorrektur einer auf der Basis
eines Betriebszustandes der Maschine festgelegten Kraftstoffeinspritzmenge durchgeführt
wird.
17. Kraftstoffeinspritzung-Steuerverfahren für eine Brennkraftmaschine mit Direkteinspritzung
(10) mit einer Zündvorrichtung zum Zünden eines Luft-KraftstoffGemisches, welche,
wenn die Maschine kalt ist, einen Kraftstoffeinspritzmodus zwischen einer Ladungseinspritzung
(batch injection), bei welcher Kraftstoff einmal während eines Ansaughubs eingespritzt
wird, und einer Aufteilungseinspritzung (split injection), bei welcher Kraftstoff
mehrmals während des Ansaughubs eingespritzt wird, schaltet,
gekennzeichnet durch:
Einstellen eines größeren Kraftstofferhöhungsbetrages für die Ladungseinspritzung
als für die Aufteilungseinspritzung, wenn eine Erhöhungskorrektur einer auf der Basis
eines Betriebszustandes der Maschine festgelegten Kraftstoffeinspritzmenge durchgeführt
wird.
18. Kraftstoffeinspritzung-Steuerverfahren für eine Brennkraftmaschine mit Direkteinspritzung
(10) mit einer Zündvorrichtung zum Zünden eines Luft-KraftstoffGemisches, welche,
nach dem Start, wenn die Maschine kalt ist, einen Kraftstoffeinspritzmodus zwischen
einer Ladungseinspritzung, bei welcher Kraftstoff einmal eingespritzt wird, und einer
Aufteilungseinspritzung, bei welcher Kraftstoff mehrmals eingespritzt wird, schaltet,
dadurch gekennzeichnet, dass,
wenn eine Erhöhungskorrektur einer auf der Basis eines Betriebszustandes der Maschine
festgelegten Kraftstoffeinspritzmenge durchgeführt wird, von dem Start der Maschine
bis zu einer vorbestimmten verstrichenen Zeitdauer der Kraftstoffeinspritzmodus auf
einen ersten Einspritzmodus gesetzt wird, bei welchem der Kraftstofferhöhungsbetrag
für die Aufteilungseinspritzung größer eingestellt wird als die Kraftstofferhöhungsmenge
für die Ladungseinspritzung und anschließend der Kraftstoffeinspritzmodus auf einen
zweiten Einspritzmodus gesetzt wird, bei welchem der Kraftstofferhöhungsbetrag für
die Ladungseinspritzung größer eingestellt wird als der Kraftstofferhöhungsbetrag
für die Aufteilungseinspritzung.
1. Appareil de commande d'injection de carburant pour un moteur à combustion interne
(10) à injection directe incluant un dispositif d'allumage pour l'allumage d'un mélange
air/carburant, qui, lorsque le moteur est froid, commute un mode d'injection de carburant
entre une injection discontinue dans laquelle le carburant est injecté une fois à
la fin d'une course de compression et une injection répartie dans laquelle le carburant
est injecté à une pluralité d'instants y compris au moins à la fin de la course de
compression, l'appareil de commande d'injection de carburant caractérisé par le fait de comprendre un moyen (20) de correction par augmentation qui règle une
quantité d'augmentation du carburant pour qu'elle soit plus élevée pour l'injection
répartie que pour l'injection discontinue en corrigeant par augmentation une quantité
d'injection de carburant établie sur la base d'un état de fonctionnement du moteur.
2. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 1, dans lequel le moyen de correction par
augmentation établit la quantité d'augmentation de carburant sur la base d'au moins
l'un parmi une température du moteur et d'un temps écoulé après le démarrage du moteur.
3. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 1 ou 2, comprenant en plus un moyen (20)
d'établissement d'un taux de répartition pour établir un taux de répartition de la
quantité d'injection de chaque injection lorsque le mode d'injection de carburant
est établi à l'injection répartie, où le moyen d'établissement d'un taux de répartition
établit le taux de répartition de la quantité d'injection de chaque injection de manière
à ce que plus la quantité totale de carburant injecté par l'ensemble des injections
de l'injection répartie baisse, plus la différence entre les taux de répartition de
la quantité d'injection baisse.
4. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 3, dans lequel le moyen d'établissement
d'un taux de répartition établit le taux de répartition de la quantité d'injection
de chaque injection de manière à ce que les taux de répartition de la quantité d'injection
deviennent égaux lorsque la quantité totale de carburant injecté par l'ensemble des
injections de l'injection répartie est inférieure ou égale à une quantité prédéterminée.
5. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 3 ou 4, dans lequel le moyen d'établissement
d'un taux de répartition établit le taux de répartition de la quantité d'injection
de chaque injection de manière à ce que la quantité d'injection de carburant de l'injection
à la fin de la course de compression soit supérieure à la quantité d'injection de
carburant de toute autre injection lorsque la quantité totale de carburant injecté
par l'ensemble des injections de l'injection répartie est supérieure à une valeur
prédéterminée.
6. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon l'une quelconque des revendications 1 à 5, dans lequel la
correction par augmentation de la quantité d'injection de carburant est effectuée
lorsque le moteur est au ralenti jusqu'à ce qu'une période de temps prédéterminée
passe après le démarrage du moteur.
7. Appareil de commande d'injection de carburant pour un moteur à combustion interne
(10) à injection directe, incluant un dispositif d'allumage pour l'allumage d'un mélange
air/carburant, qui, lorsque le moteur est froid, commute un mode d'injection de carburant
entre une injection discontinue dans laquelle le carburant est injecté une fois durant
une course d'admission et une injection répartie dans laquelle le carburant est injecté
plusieurs fois durant la course d'admission, l'appareil de commande d'injection de
carburant caractérisé par le fait de comprendre un moyen (20) de correction par augmentation qui règle une
quantité d'augmentation du carburant pour qu'elle soit plus élevée pour l'injection
discontinue que pour l'injection répartie en corrigeant par augmentation une quantité
d'injection de carburant établie sur la base d'un état de fonctionnement du moteur.
8. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 7, dans lequel le moyen de correction par
augmentation établit la quantité d'augmentation de carburant sur la base d'au moins
l'un parmi une température du moteur et un temps écoulé après le démarrage du moteur.
9. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 7 ou 8, dans lequel la correction par augmentation
de la quantité d'injection de carburant est effectuée lorsque le moteur est au ralenti
jusqu'à ce qu'une période de temps prédéterminée passe après le démarrage du moteur.
10. Appareil de commande d'injection de carburant pour un moteur à combustion interne
(10) à injection directe, incluant un dispositif d'allumage pour l'allumage d'un mélange
air/carburant, qui, après le démarrage lorsque le moteur est froid, commute un mode
d'injection de carburant entre une injection discontinue dans laquelle le carburant
est injecté une fois et une injection répartie dans laquelle le carburant est injecté
plusieurs fois, où en corrigeant par augmentation une quantité d'injection de carburant
établie sur la base d'un état de fonctionnement du moteur, du démarrage du moteur
jusqu'à ce qu'une période de temps prédéterminée passe, le mode d'injection de carburant
est établi à un premier mode d'injection dans lequel la quantité d'augmentation de
carburant pour l'injection répartie est réglée de sorte à être supérieure à la quantité
d'augmentation de carburant pour l'injection discontinue, et ensuite le mode d'injection
de carburant est établi à un deuxième mode d'injection dans lequel la quantité d'augmentation
de carburant pour l'injection discontinue est réglée de sorte à être supérieure à
la quantité d'augmentation de carburant pour l'injection répartie.
11. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 10, dans lequel dans le premier mode d'injection,
le carburant est injecté une fois lors de l'injection discontinue tandis que le carburant
est injecté à une pluralité d'instants, incluant au moins à la fin d'une course de
compression, lors de l'injection répartie, et dans le deuxième mode d'injection, le
carburant est injecté une fois durant une course d'admission dans l'injection discontinue
tandis que le carburant est injecté plusieurs fois durant la course d'admission lors
de l'injection répartie.
12. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 10 ou 11, dans lequel la quantité d'augmentation
de carburant est établie sur la base d'au moins l'un d'une température du moteur et
d'un temps écoulé après le démarrage du moteur.
13. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon l'une quelconque des revendications 10 à 12, comprenant
en plus un moyen (20) d'établissement d'un taux de répartition pour établir un taux
de répartition de la quantité d'injection de chaque injection lorsque le mode d'injection
de carburant est établi à l'injection répartie, dans lequel le moyen d'établissement
d'un taux de répartition établit le taux de répartition de la quantité d'injection
de chaque injection de manière à ce que plus la quantité totale de carburant injecté
par l'ensemble des injections de l'injection répartie baisse, plus la différence entre
les taux de répartition de la quantité d'injection baisse.
14. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon la revendication 13, dans lequel le moyen d'établissement
d'un taux de répartition établit le taux de répartition de la quantité d'injection
de chaque injection de manière à ce que les taux de répartition de la quantité d'injection
deviennent égaux lorsque la quantité totale de carburant injecté par l'ensemble des
injections de l'injection répartie est inférieure ou égale à une quantité prédéterminée.
15. Appareil de commande d'injection de carburant pour un moteur à combustion interne
à injection directe selon l'une quelconque des revendications 10 à 14, dans lequel
la correction par augmentation de la quantité d'injection de carburant est effectuée
lorsque le moteur est au ralenti jusqu'à ce qu'une période de temps prédéterminée
s'écoule après le démarrage du moteur.
16. Procédé de commande d'injection de carburant pour un moteur à combustion interne (10)
à injection directe incluant un dispositif d'allumage pour l'allumage d'un mélange
air/carburant, qui, lorsque le moteur est froid, commute un mode d'injection de carburant
entre une injection discontinue dans laquelle le carburant est injecté une fois à
la fin d'une course de compression et une injection répartie dans laquelle le carburant
est injecté à plusieurs instants y compris au moins à la fin de la course de compression,
le procédé de commande d'injection de carburant
caractérisé par le fait de comprendre l'étape qui consiste à:
régler une quantité d'augmentation de carburant pour qu'elle soit plus élevée pour
l'injection répartie que pour l'injection discontinue en corrigeant par augmentation
une quantité d'injection de carburant établie sur la base d'un état de fonctionnement
du moteur.
17. Procédé de commande d'injection de carburant pour un moteur à combustion interne (10)
à injection directe, incluant un dispositif d'allumage pour l'allumage d'un mélange
air/carburant, qui, lorsque le moteur est froid, commute un mode d'injection de carburant
entre une injection discontinue dans laquelle le carburant est injecté une fois durant
une course d'admission et une injection répartie dans laquelle le carburant est injecté
plusieurs fois durant la course d'admission, le procédé de commande d'injection de
carburant
caractérisé par le fait de comprendre l'étape qui consiste à :
régler une quantité d'augmentation de carburant pour qu'elle soit plus élevée pour
l'injection discontinue que pour l'injection répartie en corrigeant par augmentation
une quantité d'injection de carburant établie sur la base d'un état de fonctionnement
du moteur.
18. Procédé de commande d'injection de carburant pour un moteur à combustion interne (10)
à injection directe, incluant un dispositif d'allumage pour l'allumage d'un mélange
air/carburant, qui, après le démarrage lorsque le moteur est froid, commute un mode
d'injection de carburant entre une injection discontinue dans laquelle le carburant
est injecté une fois et une injection répartie dans laquelle le carburant est injecté
plusieurs fois, le procédé de commande d'injection de carburant
caractérisé en ce que :
en corrigeant par augmentation une quantité d'injection de carburant établie sur la
base d'un état de fonctionnement du moteur, du démarrage du moteur jusqu'à ce qu'une
période de temps prédéterminée passe, le mode d'injection de carburant est établi
à un premier mode d'injection dans lequel la quantité d'augmentation de carburant
pour l'injection répartie est réglée de sorte à être supérieure à la quantité d'augmentation
de carburant pour l'injection discontinue, et ensuite le mode d'injection de carburant
est établi à un deuxième mode d'injection dans lequel la quantité d'augmentation de
carburant pour l'injection discontinue est réglé pour être supérieure à la quantité
d'augmentation de carburant pour l'injection répartie.